duScrollBottomSpy issue with document.body.scrollHeight on IE11

[jrr]

We encountered an issue where under IE11, the last item in our nav was "stuck" on. Under certain circumstances, IE11 will report document.body.scrollHeight of zero, causing bottomReached to always be true in the scroll handler.

Specifically I'm seeing it with IE 11.0.9600.18059 and Angular 1.4.7.

Repro with this plunk: http://embed.plnkr.co/xKx6ATH1jtBVr2FcOeNO/preview

Pull request that fixes it: #157

[oblador]

PR was merged.